$re = '/(?<=[^/]>)[^>\P{IsBasicLatin}]*[\p{IsHiragana}\p{IsKatakana}\p{IsCJKUnifiedIdeographs}]+[^>\P{IsBasicLatin}]*(?=</)/i';
$str = '<tag3>Some text before 日本語 and some text after</tag3><tag>Before text 漢字</tag>.';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php